Shaping of hollow metal articles

ABSTRACT

Metal tubes are shaped, particularly for use as guard rail stanchions, by heating the tube in a series of bands, in order to render the tube malleable in such heated regions, and passing the heated tube between a set of rollers, one of which is shaped with a series of alternating troughs and crests whereby the crested portions act on the metal bands of the heated tube.

United States Patent [1 1 Drake 5] Dec. 25, 1973 1 SHAPING OF HOLLOW METAL ARTICLES [76] Inventor: Noel Francis Drake, Flat 3, 4 The Point Rd., Woolwich, New South Wales, Australia [22] Filed: June 1, 1972 [21] Appl. No.: 258,703

[52] US. Cl 29/155 R, 72/69, 72/107 [51] Int. Cl B2ld 13/04 [58] Field of Search 72/69, 367, 107,

[56] References Cited UNITED STATES PATENTS Andrews et a1 72/102 2,106,495 1/1938 Debor 72/69 FOREIGN PATENTS OR APPLICATIONS 1,120 1/1887 Great Britain 72/108 Primary ExaminerRichard .l. Herbst Attorney-Robert K. Rhea [57] ABSTRACT Metal tubes are shaped, particularly for use as guard rail stanchions, by heating the tube in a series of bands, in order to render the tube malleable in such heated regions, and passing the heated tube between a set of rollers, one of which is shaped with a series of alternating troughs and crests whereby the crested portions act on the metal bands of the heated tube.

6 Claims, 4 Drawing Figures SHAPING OF HOLLOW METAL ARTICLES The present invention relates to a method of and means for forming hollow articles, particularly of metal, and the products obtained thereby. The invention is also applicable to the formation of thermoplastic articles.

More particularly the present invention relates to the rolling of tubes or pipes, particularly of metal, in order to shape them as required and one particular embodiment of the invention is the manufacture of stanchions for hand-rails, guardrails and the like, more economically and easily than hitherto.

According to the invention a hollow tube, particularly a metal tube, is heated over one or more relatively narrow bands spaced along the tube and passed between a set of shaped rollers in order to produce an article or articles of the desired form.

According to one particular embodiment of the invention, a hollow metal tube, the outside diameter of which substantially equals the largest outside diameter of the article to be produced, which tube is of a convenient length, is heated by any suitable means, in a series of peripheral bands to a temperature whereby the metal in the bands is in a malleable or flowable condition. The areas of malleable metal thereby alternate with areas of relatively cooler metal, which are substantially rigid and provide support for the heated areas. Heating may be effected, for example, electrically by means of a resistance element, or by a series of gas or oil burners suitably disposed around the tube.

The heated metal tube is then supported by two plain rollers, one of which is driven and the other of which idles, and a third (shaping) roller is forced against the tube, for example, by hydraulic, pneumatic or mechanical means. The shaping roller is provided with a series of alternating troughs and crests the crests being aligned with the malleable bands of the heated tube. The metal tube is thereby reduced in diameter as desired, leaving the relatively cooler rigid parts of the tube at substantially the original diameter. The portions between the smallest diameter and the original diameter are shaped by the shaping roller into a radial or any other desired profile by the action of the crested portions of the shaping roller.

If desired the crests on the shaping roller can be spaced at intervals of, for example, 4 inches between centres, to form a series of spherical or other shapes along part or all of the length of the tube in one operation.

Alternatively the crests can be spaced at, for example, 8 inches centres or thereabouts, the process halfforming the spheres or shapes required. The operation may then be repeated by heating the tube about 4 inches away from the previously heated site and inserting the heated tube 4 inches further along the rolling machine. The shape previously formed is not affected by the second operation as it will have become relatively cool and rigid and the new indentations produce the second half of the spherical or other shape. The result is a series of spherical or other shapes alternating with short sections of circular cylindrical form or tube sections of a predetermined diameter. The shapes may be parted in the centre of this tubular section, for example, by hot or cold sawing to produce a number of substantially spherically shaped objects each with diametrically opposed spigot portions projecting therefrom preferably of an outside diameter corresponding to standard pipe sizes readily available on the open market. A handrail standard or stanchion may then be manufactured, for example, by assembling any given number of spheres in a jig with short lengths of standard pipe between and welding the whole into a continuous member. The end sphere in the assembly has its spigot portion protruding at the top and this metal may then be rolled down or beaten down to close the top of the stanchion or standard.

Hitherto, similar shapes for similar purposes have been produced by casting but such castings cannot be easily welded in a manner similar to that described in the foregoing and it has been found necessary to assemble by insertion of the short length of tube into the spigot portion and pinning or shrinking these into position. This forms a shoulder in the shape of the standard which accumulates dust and corrosive matter.

When a continuous member is completed according to the present invention, transverse holes may be drilled through the spherical sections in angular relation with respect to the axis of the spigot portions to receive conveniently sized cross members and the whole may be assembled to make a handrail or guardrail of pleasing appearance. A further advantage of the present invention is that it permits stanchion components to be drilled in order to accommodate hand rails at any desired angle, for use, for example, on stairways and the like. This represents a considerable advantage over the previously cast stanchion posts which had to be cast specially in accordance with the angle desired, at considerable expense.

The invention is illustrated by reference to the accompanying drawings in which FIG. 1 shows a length of tube with heated bands schematically represented,

FIG. 2 is an end view of a roller assembly schematically represented,

FIG. 3 is a view of one form of shaping roller,

FIG. 4 is a view of a tube after rolling.

In the drawings, a tube 1 is heated in bands as shown in FIG. 1 by any suitable means previously referred to. The heated tube is then located on the roller assembly comprising driving roller 2, idler roller 3, and shaping roller 4 which is provided with alternating crests 5 and troughs 6 (FIG. 3). The shaping roller 4 is then forced by hydraulic or other suitable means (not shown) against the heated tube whereby such tube is rolled into the shape shown in FIG. 4 comprising substantially spherical portions 7joined by cylindrical sections 8. By cutting through sections 8, components for forming into guard rail stanchions may be produced as hereinbefore described.

I claim:

1. A method of producing a handrail stanchion from a hollow metal tube comprising, heating longitudinally spaced peripheral portions of the tube, supporting and rotating the heated tube about its longitudinal axis by a driving roller and an idler roller, and forcing a shaping roller against the rotating heated tube, the shaping roller being provided with a series of alternating troughs and crests with the crests aligned with the heated peripheral portions of the tube to form a like series of substantially spherical shapes alternating with shorter sections of cylindrical form, whereby the heated portions of the tube are reduced in diameter leaving the intervening cooler portions of the tube at 5. The method according to claim 4 and further including providing a plurality of pipes diametrically equal with respect to the diameter of the spigot portions, assembling a plurality of the spherically shaped objects with the pipes by interposing a pipe length between respective spigot portions of each two adjacent spherically shaped objects, and welding the respective pipe ends and spigot portions together.

6. The method according to claim 5 and further including drilling holes through the wall of the spherical shaped objects in angular relation with respect to the axis of the spigot portions. 

1. A method of producing a handrail stanchion from a hollow metal tube comprising, heating longitudinally spaced peripheral portions of the tube, supporting and rotating the heated tube about its longitudinal axis by a driving roller and an idler roller, and forcing a shaping roller against the rotating heated tube, the shaping roller being provided with a series of alternating troughs and crests with the crests aligned with the heated peripheral portions of the tube to form a like series of substantially spherical shapes alternating with shorter sections of cylindrical form, whereby the heated portions of the tube are reduced in diameter leaving the intervening cooler portions of the tube at substantially their original diameter with those portions of the tube between the reduced diameter and the original diameter being shaped to the profile defined by the troughs.
 2. The method according to claim 1 wherein the tube is heated by electrical resistance means.
 3. The method according to claim 1 wherein the tube is heated by a burner.
 4. The methoD according to claim 1 and further including separating the spherical shapes by parting the intervening cylindrical sections substantially medially their length, to form a series of substantially spherical shaped objects each having diametrically opposed spigot portions.
 5. The method according to claim 4 and further including providing a plurality of pipes diametrically equal with respect to the diameter of the spigot portions, assembling a plurality of the spherically shaped objects with the pipes by interposing a pipe length between respective spigot portions of each two adjacent spherically shaped objects, and welding the respective pipe ends and spigot portions together.
 6. The method according to claim 5 and further including drilling holes through the wall of the spherical shaped objects in angular relation with respect to the axis of the spigot portions. 